Whatever Lawrence Krauss has written, he has certainly not written that phasers or warp drive exist, merely why they might be possible.

I think we have to distinguish between science, fictional technology based on real science and magic.
Trek is not hard but soft sci-fi. Some of its technology like impulse drive is based on fusion power, other technology like the transporter acknowledges a problem that would exist in real life via the Heisenberg compensator. Genesis or red matter are basically pure magic.

I think it is nice but not necessary that Trek tries to tie some of its fictional technologies into real science. The absence of it is certainly not a deal-breaker. Or is City on The Edge of Forever bad because it does not explain how the Guardian actually performs this neat trick? Is FC bad because we don't learn more about these funky chronitions that do the trick?

yes, this is an important point that is often overlooked. Star Trek, like Star Wars and Doctor Who, is soft sci-fi, not hard sci-fi.

The emphasis is on the story, not the potential realism of the technology or science involved.